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Journal bearings are being used in various locations of an internal combustion engine. They contribute to a large portion of total engine friction and lowering it means a significant contribution to CO2 reduction. Operating under heavy loads, journal bearings are often subject to mixed regime of lubrication where a part of bearing load is carried by asperities. This necessitates accurate modelling of asperities contact in order to get more realistic predication of friction losses in journal bearings contact. The evaluation method at Scania couples 3D confocal measurement of bearings’ surface roughness to a Multi-body Dynamic Analysis of journal bearings lubrication utilizing AVL EXCITE. During running-in, asperity peaks are reduced due to wear caused by metal-to-metal contact resulting in change of bearing surface profile and different contact zones in axial and circumferential direction. The aim of this thesis is to include these different contact zones and run-in wear profile of the bearing to the existing evaluation method at Scania to simulate run-in effects more precisely. Surface measurements were made on a run-in big end bearing surface at edges, center and region after oil hole. From these measurements, using the existing Local Scale Model at Scania, asperity pressure curve and flow factors were obtained, which were used to perform AVL EXCITE big end bearing simulations with multiple surface contact patches. The results show that the inclusion of multiple surface patches and run-in wear profile lead to a significant change in distribution and also magnitude of bearing performance parameters e.g. pressure, friction losses, clearance height. / Glidlager är en av de mest använda komponenterna i motorer. De bidrar till en stor del av motorns totala friktion och en minskning av denna bidrar i hög grad till minskade utsläpp av CO2. Glidlager som arbetar under hög last utsätts ofta för blandfilmssmörjning där en del av lasten bärs av mekanisk kontakt mellan ytornas asperiteter. Detta kräver en noggrann modellering av asperitetskontakter för att få en realistisk prediktion av friktionsförluster i glidlager.Utvärderingsmetoden på Scania kopplar ihop 3D-mätning av lagrets ytfinhet i ett konfokalmikroskåp med en dynamisk tribologiberäkning i MBS-programvaran (Multi Body Simulation) AVL Excite.Under inkörning nöts asperiteterna ner på grund av metallkontakten mellan ytorna vilket påverkar lagerytans profil och ger olika kontaktzoner i axiell och periferiell riktning.Syftet med examensarbetet är att inkludera de olika kontaktzonerna och lagrets profil efter inkörning i Scanias befintliga utvärderingsmetod i syfte att noggrannare kunna simulera inkörning av lagren.Ytfinhetsmätningar utfördes med ett konfoklamikroskop på ett inkört vevlager vid kanterna, i mitten och i närheten av oljehålet.Med hjälp av dessa mätningar och en av Scanias befintliga kontaktmodeller beräknades asperitetstryck och flödesfaktorer vilka användes för att utföra vevlagerberäkningar i AVL Excite med olika kontaktegenskaper i olika regioner.Resultaten visar att införandet av regioner på lagerytan med olika lokala kontaktegenskaper och lagerprofil efter inkörning ger en signifikant förändring av såväl storleken som fördelningen av olika lagerresultat såsom till exempel lagertryck, friktionsförluster och oljefilmstjocklek.

High heat in mechanical seals is a long-recognized main failure cause, disrupting the seal's vital lubricating film and heating temperature-sensitive process media. A way to accommodate the seal's heat generation is by choosing materials with high thermal conductivity, such as silicon carbide (SiC). In single-use and short operating time applications, the usage of SiC may be greatly over-dimensioned, unnecessarily environmentally intense, and expensive. There is a desire to apply other materials for these cases, but the heat generation of the mechanical seal poses great limitations in material selections.  The purpose of this study is to reduce the operating temperature of mechanical seals to enable the application of cheaper and more sustainable materials. The seals used for testing are presently used in Alfa Laval’s single-use separators, CultureOne, and accompanying this work is the designing of a temperature measuring rig for the specific mechanical seal to be tested in its applied environment. The following research questions have been formulated to concretize the presented problematization:     RQ1: Which parameters have the highest significance for generated heat in the single-use mechanical seal?   RQ2: How can the heat of the mechanical seal’s wear face be measured while operating in the CultureOne machine?    This study is deductive, intending to gather quantitative data through thermal measuring. The temperature measuring rig was designed with inspiration from previous similar studies and was then validated through repeated testing and comparisons with FEM-simulations of the tested case. This resulted in a detected temperature loss of 1°C, which has been accounted for in the conclusions. During validation tests, a standard original seal temperature to use as a comparison was found to be 41°C.    Heat-affecting parameters have been gathered and tested through the method of Design of Experiments (DoE), where a Placket-Burman design was chosen to enable testing 9 parameters with 12 tests. The results of the study indicate that surface roughness and sealing liquid temperature have significant effects on the seal temperature. Roughening the surface of the mechanical seal’s polished, static carbon face, as achieved with a 1000-grit abrasive paper, provided a heat mitigating effect of -9.3 °C, which is a 23% heat reduction. Similarly, introducing more cooling power to the system by cooling the sealing liquid with external methods such as an ice bath provided a heat-reducing effect of -5.4 °C at the end of a one-hour test, reducing the temperature with 13%. Combining the parameters provided a 36% reduction in heat for a one-hour run with the mechanical seal in the CultureOne Primo machine. Thus, the temperature-reducing strategies discovered in this study can be applied to enable more sustainable and cheaper material selections for mechanical face seals. / Hög temperatur i plantätningar är sedan länge uppmärksammat som en huvudsaklig haveriorsak eftersom det i många fall leder till att den smörjande vätskefilmen störs. En åtgärd för att avlägsna tätningens värme är att välja material med hög värmeledningsförmåga, som exempelvis kiselkarbid. Vid engångsapplikationer och andra tillämpningsområden med kort tid i användning har kiselkarbidtätningar ofta en överdimensionerad livslängd samtidigt som materialet är både miljöpåfrestande och dyrt i jämförelse med andra material. Således finns behovet att byta material hos tätningar i dessa applikationer, men värmegenereringen utgör hinder och begränsar alternativen i materialvalet.    Målet med denna studie är att sänka temperaturen hos mekaniska plantätningar för att möjliggöra val av billigare och miljövänligare material. Tätningarna som används för studiens experiment sitter i Alfa Lavals engångsseparator, CultureOne. Till denna studie hör framtagandet av en metod och testuppställning för att mäta temperaturen hos dessa tätningar under drift i sin tillämpade miljö. Utifrån problematiken har följande forskningsfrågor formulerats:    FF1: Vilka parametrar har störst signifikans för värmegenerering i engångstätningarna?    FF2: Hur kan temperaturen av plantätningarnas nötningsyta mätas under drift i CultureOne-maskinen?   Studien är av deduktiv natur, med insamling av primärt kvantitativa data genom temperaturmätningar. Metoden för temperaturmätning togs fram med stöd i mätmetoder från andra studier på tätningar, och mätvärdenas riktighet validerades genom kalibreringssteg, tester och jämförelser med FEM-simuleringar av tätningen. Under kalibreringen detekterades en värmeförlust på 1°C mellan uppmätt temperatur och sann temperatur av tätningens nötningsyta, vilket kompenseras för i slutsatserna. Under normala körförhållanden mättes tätningens temperatur till 41°C vilket användes som utgångspunkt att jämföra med senare experiment.    Värmegenererande parametrar för tätningar har sammanställts och testats genom en statistisk försöksplanering, där en Placket-Burman-design implementerades. Resultaten visar att ytfinhet och temperatur av tätningsvätska har signifikanta effekter för tätningens temperatur. Genom att skapa en grövre yta för plantätningens statiska halvas nötningsyta, som uppnått med ett sandpapper av finhet K1000, har en värmesänkning på -9.3 °C, motsvarande en 23% sänkning av utgångstemperaturen, uppnåtts för tätningen efter en timmes drift. På liknande sätt resulterade kylning av tätningsvätskan i en värmesänkning på -5.4 °C, vilket är 13% svalare än utgångstemperaturen. Tillsammans bidrar parametrarna till en 36% lägre temperatur hos plantätningen efter en timmes drift i CultureOne Primo-maskinen. Således skulle de testade strategierna för att sänka plantätningars temperatur kunna användas för att möjliggöra valet av miljövänligare och billigare material.

Une lubrification suffisante est essentielle au bon fonctionnement des mécanismes et/ou composants comme par exemple les paliers à roulement. Par contre, les lubrifiants contiennent souvent des débris d’usure ou des polluants extérieurs. Ces particules micrométriques peuvent pénétrer des contacts d’épaisseur inférieure au micromètre induisant des empruntes ou indents pouvant conduire à des endommagements irréversibles pour les surfaces en contact. L’objet de ce travail est l’étude du piégeage de polluants solides à l’aide de particules sphériques d’acier, d’un point de vue théorique, numérique et expérimental. Dans un premier temps, une étude phénoménologique a été proposée à l’aide d’une nouvelle méthode expérimentale basée sur la technique PIV combinée à un tribomètre bille/disque. Les trajectoires des polluants à l’entrée du contact ont pu ainsi être identifiées. En parallèle, un modèle numérique d’écoulement du lubrifiant a été développé pour permettre l’évaluation des conditions menant au piégeage ou non de particules. Finalement, des expériences sur une machine bi-disques en conditions de lubrification polluée contrôlée ont permis de valider les tendances observées pour le piégeage. Une première série de résultats a montré que le piégeage de contaminants est fortement dépendant du profil de vitesse du lubrifiant. Un taux de piégeage très hétérogène a été observé sur des contacts avec une ellipticité transverse à l’écoulement variable. De manière surprenante, malgré une augmentation de la largeur de contact, une forte diminution du nombre de particules piégées a été observée dans des contacts elliptiques. Il a été démontré que cette diminution pouvait être imputée à la présence d’importants reflux de lubrifiant dans les contacts elliptiques larges. L’étude de contacts hybrides, nitrure de silicium–acier, a montré une bonne résistance à l’indentation du nitrure de silicium. Il est à noter que les contacts hybrides présentent des niveaux de piégeage similaire à un contact tout acier. / Contact lubrication is essential in a wide range of mechanical systems like rolling element bearings (REBs). A minimum quantity of clean lubricant all along the bearing life is necessary but difficult to ensure. In fact, lubricants contain inevitably wear debris or external particles, like dust. Carried by the lubricant in the vicinity of elastohydrodynamic (EHD) contacts, particles can be entrapped with disastrous consequences for contacting surfaces. Entrapment of micrometric particles in submicrometric contacting gaps means irreversible damages for the surfaces. Damages weaken the surfaces and reduce significantly the REBs lifetime. The goal of this work is to analyze the critical particle entrainments in the contact inlet. Entrapment of steel spherical particles was investigated from the numerical and experimental point of view. Firstly, the phenomenology of entrapment was explored with a new experimental method based on Particle Image Velocimetry (PIV) technique installed on a tribometer. It enabled the evaluation of velocity profiles in the contact inlet and the tracking of particles within EHD contacts. Secondly, a numerical modelling of the inlet flow for EHD contacts, including the particle tracking, was developed. Finally, tests on a twin-disc machine with a controlled level of well-defined contamination were conducted to validate previous conclusions. A first set of results showed that particle entrapment is highly dependent on the lubricant velocity profile. Depending on contact geometry, from point to wide elliptical contacts, different entrapment probability were revealed. Surprisingly, increasing contact width with wide elliptical contacts leads to a drop of entrapped particles. It was demonstrated that this phenomenon is due to backflows occurring upstream from these contacts. Introducing a hybrid pair of contacting materials (silicon nitride–steel), dents on the surfaces due to entrapped particles were explored. It has been confirmed that silicon nitride surface offers a real ability to resist to indentation. It was also noticed that the entrapment probability for silicon nitride–steel contacts is equivalent to a steel–steel one.

Icing severely affects society, especially in the Nordic countries. Iceaccumulation can result in critical performance problems and safetyconcerns for instance in road, air and sea transportation, transmissionlines, marine and offshore structures, wind turbines and heat exchangers.Present active ice-combating approaches possess environmental,efficiency and cost drawbacks. Thus, fabricating icephobic surfaces orcoatings impeding ice formation (anti-icing), but facilitating ice removal(de-icing) is desired. However, different conditions in the environmentduring ice formation and growth add to the complexity of the problem.An icephobic surface that works for a certain application might not be agood candidate for another. These surfaces and the challenges are infocus in this thesis.Wetting properties are important for ice formation on surfaces fromthe liquid phase (often supercooled water), where the water repellency ofthe surfaces could enhance their anti-icing effect. Considering this,different hydrophobic and superhydrophobic surfaces with differentchemistry, morphology and roughness scale were prepared. Since anyinduced wetting state hysteresis on hydrophobic surfaces could influencetheir performance, the wetting stability was investigated. In particulardynamic wetting studies of the hydrophobic surfaces revealed whatsurface characteristics benefit a stable wetting performance. Further, theeffect of temperature, particularly sub-zero temperatures, on the wettingstate of flat and nanostructured hydrophobic surfaces was investigated.This was complemented with studies of the wetting stability of sessilewater droplets on flat to micro- and multi-scale (micro-nano) roughhydrophobic samples in a freeze-thaw cycle. To be consistent with mostapplications, all temperature-controlled experiments were performed inan environmental condition facilitating frost formation. Further, antiicingproperties of hydrophobic surfaces with different topography butsimilar chemistry were studied by freezing delay measurements.A dynamic wetting study using hydrophobic samples with similarchemistry but different topography revealed that multi-scale roughnesscould benefit the wetting stability. However, when these surfaces areutilized at low temperatures the wetting hysteresis observed during acooling/heating cycle is significant. Such a temperature-inducedhysteresis is also significant on superhydrophobic surfaces. I attributethis to condensation followed by frost formation facilitating spreading of  the supercooled water droplet. The freezing delay measurementsdemonstrate no significant effect of surface topography on anti-icingproperties of hydrophobic surfaces, however the flat surfaces showed thelongest delay. These findings are in agreement with heterogeneous icenucleation theory, suggesting preferential ice nucleation in concave sites,provided they are wetted.In the second part of this thesis, I consider the findings from theprevious part illustrating the limitations of (super)hydrophobic surfaces.The de-icing properties of hydrophilic surfaces with a hydration waterlayer, hypothesized to lubricate the interface with ice, were studied. Heretemperature-controlled shear ice adhesion measurements, down to -25oC, were performed on an adsorbed layer of a polymer, either bottle-brushstructured poly(ethylene oxide) or linear poly(ethylene oxide). The iceadhesion strength was reduced significantly on the bottle-brushstructured polymer layer, specifically at temperatures above -15 oC,whereas less adhesion reduction was observed on the layer formed by thelinear polymer. These findings are consistent with differential scanningcalorimetry (DSC) data, demonstrating that the hydration water, boundto the bottle-brush structured polymer, is in the liquid state at thetemperatures where de-icing benefit is observed. Further, continuingwith the hypothesis of the advantage of surfaces with a natural lubricantlayer for de-icing targets, I studied shear ice adhesion on the molecularlyflat basal plane of hydrophilic mica down to -35 oC. Interestingly, ultralowice adhesion strength was measured on this surface. I relate this to theproposed distinct structure of the first ice-like but fluid water layer onmica, with no free OH groups, followed by more bulk liquid-like layers.This combined with the molecularly smooth nature of mica results in aperfect plane for ice sliding. / Isbildning har en stark inverkan på samhället, speciellt i de nordiskaländerna. Isuppbyggnad kan resultera i kritiska prestandaproblem ochsäkerhetsrisker inom t.ex. väg-, luft-, och sjötransport, kraftledningar,marina- och offshorestrukturer, vindkraftverk och värmeväxlare.Nuvarande aktiva isbekämpningsmetoder uppvisar brister i avseende påmiljö, effektivitet och kostnad. Det finns därmed ett behov av attframställa ytor eller ytbeläggningar som förhindrar isbildning (antiisning)eller underlättar borttagandet av redan bildad is (avisning). Dockkompliceras problemet av de många olika förhållanden under vilka is kanbildas. En beläggning som fungerar för en viss tillämpning behöver intenödvändigtvis vara en bra kandidat för en annan. Dessa ytor ochutmaningar relaterade till dem är i fokus i denna avhandling.Vätningsegenskaper är viktiga för isbildning på ytor från vätskefas(ofta underkylt vatten), och det har visats att vattenavstötande ytor i vissasammanhang kan motverka isbildning. Med detta i åtanke framställdesolika hydrofoba och superhydrofoba ytor, med varierande kemi,morfologi och ytråhet. Eftersom en förändring i de hydrofoba ytornasvätningsegenskaper kan påverka deras funktion studerades vätningsstabilitetenför dessa ytor. I synnerhet dynamiska vätningsstudier av dehydrofoba ytorna avslöjade vilka ytegenskaper som är fördelaktiga förvätningsstabiliteten. Vidare studerades hur temperaturen, särskilt undernoll grader, påverkar vätningstillståndet på släta och nanostruktureradehydrofoba ytor. Arbetet kompletterades med studier av vätningsstabilitetenför vattendroppar på släta samt mikro- och multistrukturerade(mikro-nano) hydrofoba ytor under flera frysningsupptiningscykler.För att vara i linje med de flesta tillämpningar, utfördesalla temperaturkontrollerade mätningar i en miljö där frost kunde bildaspå ytorna. Anti-isegenskaperna hos de hydrofoba ytorna med varierandetopografi men samma kemi studerades vidare genom att studera hur långtid det dröjde innan en vattendroppe på ytan fryste vid en visstemperatur.De dynamiska vätningsstudierna på hydrofoba ytor med samma kemimen olika topografi avslöjade att en ytråhet på flera längdskalor kan haen positiv inverkan på vätningsstabiliteten. När dessa ytor är exponeradeför låga temperaturer är dock vätningshysteresen under en nedkylnings-/uppvärmnings-cykel significant. Den temperatur-inducerade hysteresenär också betydande för superhydrofoba ytor. Detta tillskriver jag  kondensation på ytan som följs av frostbildning, vilket i sin tur möjliggörspridning av den underkylda vattendroppen på ytan. Mätning avfördröjningen i frysningsförloppet påvisade ingen betydande effekt avyttopografin för hydrofoba ytor, men släta hydrofoba ytor uppvisade denlängsta fördröjningen. Dessa resultat är i överensstämmelse med rådandeheterogen iskärnbildningsteori, som visar på fördelaktig iskärnbildningpå konkava delar av ytan, förutsatt att dessa väts.I den andra delen av avhandlingen utnyttjar jag observationerna frånden första delen vilka illustrerade begränsningarna för superhydrofobaytor, och söker en annan lösning. Avisningsegenskaper för hydrofilastarkt hydratiserade ytor studerades, med hypotesen att hydratiseringkan smörja gränsskiktet med is. Temperatur-kontrolleradeisadhesionsmätningar ned till -25 °C utfördes på adsorberade skikt av enpolymer med många sidokedjor av polyetylenoxid (”bottle-brush”), såvälsom på ett skikt av linjär polyetylenoxid. Isadhesionen blev kraftigtreducerad på ”bottle-brush”-polymeren, speciellt vid temperaturer högreän -15°C. Däremot kunde knappast ingen minskad isadhesion observerasför den linjära polymeren. Dessa observationer överensstämmer meddifferentialskanningskalorimetri (DSC) data, som visar att dethydratiserade vattenskiktet, vilket är bundet till ”bottle-brush”-polymeren, är i vätskeform vid de temperaturer där avisningsfördelar ärobserverade. För att vidare undersöka hypotesen att det vore fördelaktigtmed ett naturligt smörjande skikt på ytan för att uppnå godaavisningsegenskaper, utförde jag isadhesionsmätningar på molekylärtsläta glimmerytor ner till -35 °C. Intressant nog uppmättes extremt lågisadhesion på denna yta. Detta relaterar jag till den föreslagna utprägladehydratiseringsstrukturen, bestående av ett första is-liknande vattenskiktutan fria OH-grupper, följt av ett mer bulkliknande skikt. Detta ikombination med den molekylärt släta naturen hos glimmer resulterar iett perfekt plan för isen att glida på. / <p>QC 20160504</p> / TopNano

[pt] O presente trabalho apresenta um modelo simplificado baseado na teoria de lubrificação e conceito de viscosidade equivalente para estudar o escoamento dos fluidos de perfuração através de um espaço anular excêntrico com rotação da coluna de perfuração. Em razão do comportamento não Newtoniano destes fluidos, é significativa a influência da rotação da coluna na perda de carga, já que a viscosidade dos fluidos varia com a taxa de deformação imposta. Uma completa análise deste problema requer uma solução tridimensional da equação de conservação de quantidade de movimento de fluidos não Newtonianos, cuja solução é extremamente cara computacionalmente, tornando necessário o desenvolvimento de modelos simplificados que descrevam bem os principais fenômenos observados nestes escoamentos. No modelo proposto, as equações que governam o escoamento são simplificadas pela teoria da lubrificação em coordenadas cilíndricas. Desta forma, o escoamento tridimensional é descrito por uma única equação diferencial bidimensional para o campo de pressão. O comportamento mecânico do fluido é avaliado através do método da Viscosidade Newtoniana Equivalente. O modelo proposto foi validado a partir de soluções numéricas para o modelo completo, disponíveis na literatura, avaliando a precisão das simplificações adotadas. Os resultados mostram o intervalo no qual o modelo simplificado é preciso e apresentam o efeito das propriedades dos fluidos, da geometria do poço e da rotação da coluna na perda de carga do escoamento.O presente trabalho apresenta um modelo simplificado baseado na teoria de lubrificação e conceito de viscosidade equivalente para estudar o escoamento dos fluidos de perfuração através de um espaço anular excêntrico com rotação da coluna de perfuração. Em razão do comportamento não Newtoniano destes fluidos, é significativa a influência da rotação da coluna na perda de carga, já que a viscosidade dos fluidos varia com a taxa de deformação imposta. Uma completa análise deste problema requer uma solução tridimensional da equação de conservação de quantidade de movimento de fluidos não Newtonianos, cuja solução é extremamente cara computacionalmente, tornando necessário o desenvolvimento de modelos simplificados que descrevam bem os principais fenômenos observados nestes escoamentos. No modelo proposto, as equações que governam o escoamento são simplificadas pela teoria da lubrificação em coordenadas cilíndricas. Desta forma, o escoamento tridimensional é descrito por uma única equação diferencial bidimensional para o campo de pressão. O comportamento mecânico do fluido é avaliado através do método da Viscosidade Newtoniana Equivalente. O modelo proposto foi validado a partir de soluções numéricas para o modelo completo, disponíveis na literatura, avaliando a precisão das simplificações adotadas. Os resultados mostram o intervalo no qual o modelo simplificado é preciso e apresentam o efeito das propriedades dos fluidos, da geometria do poço e da rotação da coluna na perda de carga do escoamento.O presente trabalho apresenta um modelo simplificado baseado na teoria de lubrificação e conceito de viscosidade equivalente para estudar o escoamento dos fluidos de perfuração através de um espaço anular excêntrico com rotação da coluna de perfuração. Em razão do comportamento não Newtoniano destes fluidos, é significativa a influência da rotação da coluna na perda de carga, já que a viscosidade dos fluidos varia com a taxa de deformação imposta. Uma completa análise deste problema requer uma solução tridimensional da equação de conservação de quantidade de movimento de fluidos não Newtonianos, cuja solução é extremamente cara computacionalmente, tornando necessário o desenvolvimento de modelos simplificados que descrevam bem os principais fenômenos observados nestes escoamentos. No modelo proposto, as equações que governam o escoamento são simplificadas pela teoria da lubrificação em coordenadas cilíndricas. Desta forma, o escoamento tridimensional é descrito por uma única equação diferencial bidimensional para o campo de pressão. O comportamento mecânico do fluido é avaliado através do método da Viscosidade Newtoniana Equivalente. O modelo proposto foi validado a partir de soluções numéricas para o modelo completo, disponíveis na literatura, avaliando a precisão das simplificações adotadas. Os resultados mostram o intervalo no qual o modelo simplificado é preciso e apresentam o efeito das propriedades dos fluidos, da geometria do poço e da rotação da coluna na perda de carga do escoamento. / [en] In this work a simplified model based on the Lubrication Theory and on the equivalent viscosity is presented to study the drilling fluid flow dynamics through an eccentric annular space with rotation of the drilling column. As a result of the non-Newtonian behavior of the fluid, the rotation of the column has a significant impact on the pressure drop since the viscosity of the fluids is a function of the strain rate applied. A complete analysis of this problem requires a tridimensional solution of the equation of momentum conservation, which makes the solution computationally expensive. For such, simplified accurate models that describe the main phenomena observed have to be developed. On the proposed model, the flow dynamics equations are simplified by the Lubrication Theory in cylindrical coordinates. Therefore, the tridimensional flow is described by one single two dimensional equation for the pressure field. The mechanical behaviour of the fluid is evaluated through the Equivalent Newtonian Viscosity method. The proposed model, as well as the accuracy of the simplifications used, was validated by comparison with numerical solutions of the complete set of equations available on the literature. The results show the range in which the proposed simplified model is accurate and presents the effects of the fluids properties, well geometry and column rotation on the pressure loss.

Made available in DSpace on 2016-07-27T14:20:53Z (GMT). No. of bitstreams: 1 Tayssa Andrade Batista Novato Machado.pdf: 1002749 bytes, checksum: fcfda75cce20c8e392a6858cdf2c5c06 (MD5) Previous issue date: 2015-08-31 / The present study aimed at modifying difficult (awkward) actions related to sexual behavior, such as comments related to dissatisfaction with the partner and the use of artificial lubricants, through general and specific behavioral interventions. With respect to general behavioral interventions we applied several techniques, like instruct through information, provide feedback, prioritize tasks, and provide models and instructions as positive reinforcement, while with specific behaviors we included teaching discriminative training of bodily responses before and during sexual intercourse. In addition, as a case study, it aimed to evaluate the antecedents and consequences of sexual dysfunction reported by a participant female of 26 years with a stable partner. The functional evaluation included procedures through an interview and a questionnaire. Further, we also used behavioral logging activity (self-monitoring). To demonstrate that interventions (independent variable) had effect on the dependent variable we used the design of alternating-type treatments (ABC) succeed by follow-up. The results showed decrease in behaviors-problem and increase of skilled actions related to sexual behavior, such as reports of satisfaction with the partner and vaginal lubrication response. / O presente estudo objetivou a modificação de ações inábeis relacionadas ao comportamento sexual, bem como dos relatos de insatisfação com o parceiro e do uso de lubrificantes artificiais, por meio de intervenções comportamentais gerais (instruir por meio de informações, fornecer feedbacks, hierarquizar tarefas, fornecer modelos e instruções e instruir o uso do reforçamento positivo) e específicas (ensinar o treino discriminativo das respostas corporais antes do coito e ensinar o treino discriminativo das respostas corporais durante o coito). Ainda objetivou avaliar os antecedentes e consequentes da disfunção sexual relatada por uma participante do sexo feminino, de 26 anos e com parceiro fixo. A avaliação funcional incluiu procedimentos indiretos por meio de uma entrevista e de um questionário. Também utilizou-se de uma atividade de registro comportamental (auto-observação). Para demonstração de que as intervenções (variável independente) é que produziram efeito sobre a variável dependente, foi empregado o delineamento de tratamentos alternados do tipo (ABC) seguido por follow-up. Os resultados demonstraram diminuição dos comportamentosproblema e aumento de ações hábeis relacionadas ao comportamento sexual, de relatos de satisfação com o parceiro e da resposta de lubrificação vaginal.

Le contact Segment-Piston-Chemise (SPC) est essentiel pour la réduction des émissions de CO2 et de polluants dans les moteurs automobile. Pour optimiser ces deux contraintes antagonistes, il est nécessaire d’étudier l’influence de la microgéométrie afin de trouver de nouvelles architectures de ce contact. L’étude expérimentale étant très coûteuse, il est impératif de pouvoir modéliser les performances du contact SPC. Les méthodes multigrilles permettent de réduire considérablement les temps de calcul. Pour le contact SPC, les méthodes multigrilles classiques perdent leur efficacité en présence de texture. Un nouvel algorithme, basé sur des idées développées par Alcouffe et al. a été conçu qui permet l’étude du contact hydrodynamique en présence de texturation importante. Il a été validé par comparaison avec un modèle analytique 1D, ses performances ont été étudiées et une première étude de l’influence des paramètres sur la portance pour une surface striée a été faite. L’algorithme a ensuite été modifié pour imposer la conservation des flux. Un processus de relaxation plus proche de la physique du phénomène est utilisé. Le code obtenu n’atteint pas l’efficacité multigrille optimale. Cependant sa convergence est suffisamment rapide pour étudier l’influence de pores pour le segment plat et montrer l’importance d’une texturation partielle. Pour finir, le terme transitoire de l’équation de Reynolds est pris en compte. Pour un segment parabolique et une chemise striée, l’influence des paramètres des stries (profondeur, largeur, distance et angle des stries) sur la variation moyenne de la hauteur de film par rapport à une surface lisse est analysée. / The piston ring cylinder liner (PRCL) contact is essential in the CO2 and pollutant emission reduction in internal combustion engine. These two constraints being antagonistic, a compromise has to be found and it is necessary to study the microgeometry influence in order to find new PRCL contact architectures. As experimental study can be very expensive, modeling PRCL contact performance becomes crucial. Multigrid methods allow a huge reduction of the computational time. Unfortunately, in presence of texture, classical multigrid efficiency decays significantly and are not usable. A new algorithm based on an approach developed by Alcouffe et al. was designed that allows the study of the hydrodynamic lubrication of this contact even in the case of a highly varying geometry due to the texture. The obtained code was validated by comparison with a 1D analytical model, its performance was evaluated and a first study of an analytic cross hatched geometry parameter influence on the load carrying capacity was completed. The code was modified to include flow conservation. A relaxation process based closer to the physics phenomenon is used. The code efficiency is not the one that is expected from multigrid technics. However it convergence is sufficiently fast to study the dimple influence for the oil control ring and show the importance of partial texturing. Finally the transient term of the Reynolds equation is accounted for. In the case of a parabolic ring and for a cross hatched liner, the influence of the groove parameters ( depth, width, distance and groove angle) on the average minimum film thickness with respect to the smooth case is analyzed.

Depuis plusieurs années à nos jours, les paliers à gaz sont utilisés avec succès sur une large gamme de turbo-machines. Certains de ces systèmes sont utilisés dans des environnements de contrôle de l’environnement par gaz réfrigérant. Dans ce travail, nous présentons un modèle théorique et numérique qui tient compte de la transition du lubrifiant vapeur / liquide, la transition de l’écoulement laminaire / turbulent et les variations 3D de la viscosité et de la température dans le fluide et les solides pour les deux situations statiques et dynamiques. Ce modèle comporte : la résolution de l'équation de Reynolds généralisée pour les fluides compressibles à viscosité variable en 3D, la description des effets de la turbulence en utilisant l'approche phénoménologique de Elrod, en utilisant un champ de viscosité turbulente 3D, la résolution de l’équation d’état non linéaire du lubrifiant, capable de décrire la transition vapeur / liquide et une approche thermique local afin d'obtenir une estimation 3D de la température du fluide, grâce à l'équation d'énergie pour film mince. La prise en compte également des effets thermiques dans les solides. Dans cette étude, nous avons montré l'importance d'une description précise des paramètres du film fluide, dont les variations influencent largement le comportement du palier. Parmi les principales théories, il y a: lubrifiant compressible, avec un comportement non-linéaire près de la transition vapeur / liquide, la transition vapeur / liquide et le calcul des paramètres équivalents du mélange, un écoulement turbulent du fluide pour le palier GFB à grande vitesse en utilisant un modèle 3D de la viscosité turbulente, un comportement 3D pour la viscosité, en particulier les variations inter-films (dépendant de la température), et un comportement 3D pour la température, en particulier dans le sens transversal du film afin d'être compatible avec la viscosité, mais également dans la direction axiale afin de tenir en compte du gradient de température potentiel qui modifie considérablement le profil 3D de la température du palier. Ces deux comportements statiques et dynamiques du palier compliant GFB sont analysés. / For years now, gas bearings are successfully used over a large panel of turbo-machineries. Some of these systems are bound to be run in controlled environments such as refrigerating gas. In this work we present a theoretical and numerical model which takes into account the vapor/liquid lubricant transition, the laminar/turbulent flow transition and both temperature and viscosity 3D variations in the fluid and the solids for both static and dynamic situations. This model involves: the resolution of the generalized Reynolds equation for compressible fluids with 3D variable viscosity, the description of the turbulence effects by the phenomenological approach of Elrod, using a 3D eddy viscosity field, the resolution of a non-linear equation of state for the lubricant, able to describe the vapor/liquid transition and a local thermal approach to obtain a 3D estimation of the fluid temperature, thanks to the thin-film energy equation. The thermal effects in solids are also taken into account. In this study, we showed the importance of an accurate description of the film parameters, which variations largely influence the bearing behaviour. Among the principal theories, there are: compressible lubricant, with an appropriate non-linear behaviour when close to the vapor/liquid transition, vapor/liquid transition and calculation of the mixture equivalent parameters, turbulent flow for high-speed GFBs with a 3D eddy viscosity mode, a 3D behaviour for viscosity, particularly the cross-film variations, (temperature dependent)and a 3D behaviour for temperature, particularly in cross-film direction in order to be consistent with viscosity, but also in the axial direction in order to account for potential temperature gradient which considerably modifies the bearing 3D temperature profile. Both static and dynamic behaviours of GFBs are analysed.